High Coolant Temps! HELP!

[KarenS144]

We're about 20 miles from home and sitting in a church parking lot after the alarm sounded to tell us about the high coolant temp.

The engine fan isn't running so we think that is the problem but don't know what to check or do.

HELP!!

[Skip426]

Does your coach have a side radiator?

Freightliner or Spartan chassis?

[KarenS144]

Freightliner. Cummins engine. No side radiator.
Newmar Ventana

[Skip426]

I don't know if there is a method to activate the rad fan on a rear rad unit.
But Freightliner may be able to help.

Freightliner free help line

1-800-385-4357 have your serial number handy.

Is the alternator showing charge ? The engine may have broken the serpentine belt.

[KarenS144]

We made it to a Freightline dealer. Temp was fine & no alarms. We'd unhooked the Jeep to turn around in the parking lot and drove about 25 miles with me following the coach. The Jeep has tagged along with us every time we've been out so I can't see where it would make a difference.

[KarenS144]

Fan was on when we got to Freightline dealer & we're on the road again. Fan is on, temp is right where it should be on the gauge. Freightline guy said they couldn't look at it till Friday at the earliest and since the fan is running and the temp is good, just to drive it. OR.. we could run up a big bill and maybe still not figure out why it did what it did. He also said that no way could the engine have gotten that hot in the short distance it was driven.

We've had a ton of rain over the past several days and the outside temps are in the low 50s. We turned the dash heater on and shortly after that was when we got the alarm. We've been on the road for over an hour now & turned the heater on a few minutes ago and no changes on the temp.

It's a mystery....

[topdownman]

This sounds strange since the rear radiator units have a belt driven fan, unless the fan clutch just let completely go. Did it really get hot?

[TeJay]

It is possible that the thermostat stuck once and caused the high temps. Maybe it was a relay that stuck once and the fan didn't come on. Either of those could cause an intermittent issue. Yes, they are always the most difficult to locate.

Many time relays used on vehicles are all the same or at least a good number of them are. That means you could swap one for another and maybe find the problem when it happens. Check your fuse box for relays and fine one for the fan (if it's electric). I'm not as familiar with the diesel rigs.

TeJay

[KarenS144]

Warning alarm sound, warning on dash & gauge was in the red. We don't have anything to tell us exactly what the temp was though.

Could have turning the dash heater on before the engine got warmed up have caused the engine fan not to come on when it should have?

We're still motoring along & temp is fine. The temp gauge is about still below the middle mark and we left the Freightline dealer about 2 hours ago running 62ish on the interstate & 55 (speed limit) now.

[Skip426]

This is a big guess , at a possible cause for your problem.
IF !! , there was an air pocket in the dash heater, and turning the heater on moved the air to the cylinder head at the thermostat, the thermostat would not have opened, because the trapped air wouldn't transfer enough heat to the thermostat to activate it. There is a small air bleed hole in the thermostat, that over the time you sat at the side of the road would have cleared the air and allowed the t'stat to function properly.
Check your engine coolant level , cross your fingers that it was a one off problem, and have a safe trip.

Not sure of the control on your engine fan, some use a temperature sensitive fluid in the fan hub, others have electronic controls. The type with a fluid hub, are activated by air temperature at the rad, and if the engine thermostat didn't open the rad was still cool and the fan would not ramp up to full speed.

[KarenS144]

Skip426,

Gary feels it's got to be something weird like that. It was the first time we'd had the heater on. The engine coolant level was fine when it was checked shortly after we stopped in the parking lot. That was fun.....pouring rain & we couldn't get turned around without taking the Jeep off which was in a bind by that time.

We'll see how things go on Sunday when we head home.

[topdownman]

There is a burp valve on the rear of the coach that lets air out of the cooling system. I think Skip426 is right.

[Skip426]

Keep the Freightliner help line phone number handy, and when you get home , take some time and sign up for " Access Freightliner " takes a while , but well worth the time. You get online access to parts and wiring info, for your RV's chassis. Having that info has saved me a couple of times over the 4 years I've owned my coach.
Air system diagrams and wiring schematics are particularly helpful.

It's been a few years since I signed up, when I did , you had to phone the help line, with your serial number, things may be different now.

www.accessfreightliner.com

[KarenS144]

Originally Posted by Skip426

Keep the Freightliner help line phone number handy, and when you get home , take some time and sign up for " Access Freightliner " takes a while , but well worth the time. You get online access to parts and wiring info, for your RV's chassis. Having that info has saved me a couple of times over the 4 years I've owned my coach.
Air system diagrams and wiring schematics are particularly helpful.

It's been a few years since I signed up, when I did , you had to phone the help line, with your serial number, things may be different now.

www.accessfreightliner.com

Thanks, Skip426!